Safety device for escalators



1966 MlNEJlRO JlN ETAL 3,

SAFETY DEVICE FOR ESCALA'IORS Filed April 2, 1964 2 Sheets-Sheet 1 INVENTORS mmelmro 3m Tikcs Hare BY @QLJLW.

ATTORNEY Feb. 8, 1966 MlNEJlRO JlN ETAL 3,233,717

SAFETY DEVICE FOR ESCALATORS Filed April 2, 1964 2 Sheets-Sheet 2 INVENTOI6 mmem J hi Hay- BY GOLZ-JQJL ATTORNEY United States Patent Ofiice 3,233,717 Patented Feb. 8, 1966 3,233,717 SAFETY DEVICE FOR ESCALATORS Minejiro Jin and Takeshi Hara, Katsuta-shi, Japan, assignors to Hitachi, Ltd., Tokyo, Japan, a corporation of The present invention relates to escalators and more particularly to a safety device disposed at a landing platform from escalators.

Escalators comprise an endless flight of footsteps, each of which is generally provided with a riser and a tread having a plurality of cleats extending in the advancing direction of the staircase. At a landing platform from the escalator, there is provided a comb-shaped plate which has also a plurality of cleats through which the cleats of the treads are made to pass in interengaging relation therewith. Recent trends in the structure of the escalator are toward narrowing the clearances between the cleats of the treads and the comb-shaped plates in order to ensure a greater degree of safety for passengers. Thus, smallest possible clearances are generally recently provided between the stationary and moving cleats.

Therefore, if the footstep swings in the lateral direction or rises above the normal level during its travel for some reason or if the comb-shaped plate is bent downwardly with its tip drooping downwardly beyond its normal level, the tread on the footstep may collide with the -com-b-shaped plate to break the same. In addition to the above, the footstep may further collide with the comb shaped plate to damage the latter, and in the worst case a foot of a passenger may get jammed between the footstep and the comb-shaped plate. Since the footsteps are connected by an endless chain to form an endless linkage and are moved for endless circulation, the footsteps may successively collide with the comb-shaped plate until the escalator is brought to a halt, thus bringing forth heavy damage.

The present invention intends to eliminate any possibility of occurrence of such detrimental accident, and has for its object to provide a safety device which is operative in response to any breakage of a comb-shaped plate to abruptly stop the operation of an escalator to thereby prevent a footstep from colliding with the comb-shaped plate or to minimize the accident to an extent that at worst one footstep only may collide with the comb-shaped plate.

According to the invention, there is provided a safety device for an escalator comprising a plurality of combshaped plates disposed in juxtaposed relation to each other on a landing plate provided at a landing floor from the escalator, said comb-shaped plates each having a plurality of cleats extending in the direction towards the advancing direction of the escalator and arranged for meshing engagement with cleats of a tread provided on a movable footstep, an electrical conductor disposed transversely across the entire width of said comb-shaped plates, said electrical conductor being so arranged that the flow of current therethrough is interrupted in the event of breakage of any one of said comb-shaped plates, and means operative in response to the interruption of the cur-rent flow through said electrical conductor to stop the operation of the escalator.

There are other objects and particularities of the invention which will become obvious from the following description with reference to the accompanying drawings, in which:

FIG. 1 is a side elevational view, with parts in longitudinal section, of a landing platform from an escalator to which a safety device of the invention is applied;

FIG. 2 is an enlarged longitudinal sectional view of part of FIG. 1;

FIG. 3 is a fragmentary enlarged front elevational view taken along the line B-B of FIG. 2; and

FIG. 4 is a plan view of FIG. 2.

The invention will now be described more specifically with reference to the drawings. In the drawings, especially in FIGS. 1 and 2, there is shown an escalator which comprises a multiplicity of footsteps 1, each of which is supported on means including a front wheel 2. A tread 4 is firmly secured to the upper face of each footstep 1, and has a plurality of cleats 4' extending in the advancing direction of the staircase and grooves defined therebetween. The front wheels 2 are directly connected with each other in endless linkage by a footstep driving chain 5 which is driven by a sprocket wheel 6. A sprocket wheel 7 is coaxially mounted on the shaft of the sprocket wheel 6 and a transmission chain 8 is trained about the sprocket wheel 7 and a sprocket wheel 9 connected to a motor 33. Therefore, driving power developed by the motor 33 is transmitted by way of the sprocket wheel 9, chain 8, sprocket wheel 7 to the sprocket wheel 6 to drive the footsteps 1 for endless circulation.

In FIGS. 3 and 4, there are shown a plurality of, say three, comb-shaped plates 12, 13 and 14 which are fitted 1n uxtaposed relation to each other to a landing plate 11 which is provided at a floor Ill (FIG. 1). Each of the comb-shaped plates 12, 13 and 14 has cleats 15 which extend towards the cleats 4 of the tread 4. The combshaped plates 12, 13 and 14 are fittedto the landing plate 11 by means such as fitting screws 16.

As commonly known, the cleats 4 of the tread 4 protruding upwardly from the upper face of the footstep 1 are arranged to move past the comb-shaped plates 12, 13 and 14 by fitting in clearances A between the cleats 15 of the comb-shaped plates so that feet of passengers ridmg on the footstep 1 can safely be transferred to the upper floor. The comb-shaped plates 12, 13 and 14 are provided with sufiicient strength to support the weight of passengers, but are so designed that, when anything is pinched between the cleats 15 thereof and the cleats 4 of the tread 4 or when the footstep 1 collides with the cleats 15 for any reason, the comb-shaped plates break in the vicinity of a portion P as shown in FIG. 2 in order to protect the footstep 1 from being damaged. In such a case, however, the escalator must automatically be stopped immediately lest a foot of a passenger should get jammed between the landing plate 11 and the tread 4 of the footstep 1.

Hereinunder, detailed explanation of an embodiment of a safety device of the invention will be given with reference to FIGS. 2, 3 and 4. As shown in the drawings, a recess 23 is for-med in the transverse direction of each of the comb-shaped plates 12, 13 and 14 in aligned relation with each other, and electrical conductors 17, 1d and 19 are inserted in the recesses 23 of the plates 12, 13 and 14, respectively. On opposite ends of the electrical conductors 17, 18 and 19, there are provided conductive pieces (contacts) 20 and 20, 21 and 21 and 22 and 22, respectively. Therefore, when the combshaped plates 12, 13 and 14 are juxtaposed as shown in FIG. 4, the conductive pieces, for example, 21 and 20' are securely brought to contact with each other as shown in PlG. 3. The conductive pieces 20 and. 22' provided at the extremities of the juxaposed comb-shaped plates 12 and 14 are electrically connected to a protective relay 28 by way of contact members 26 and 27 connected to ends of electrical wires 24 and 25 provided on the body of the escalator, respectively. A contact 29 of the protective relay 28 is interposed in a control circuit 30 3 for controlling the operation of the escalator driving motor, as shown in FIG. 4.

In the normal steady operation, the electrical conductors 1'7, 18 and 19 disposed in the respective comb-shaped plates 12, 13 and 14 are electrically connected tothe electrical wires 24 and 25 through the respective conductive pieces 20, 20', 21, 21, 22 and 22' and the contact members 26 and 27, as shown in FIG. 4. In the event that one of the juxtaposed comb-shaped plates, for example, the comb-shaped plate 13 breaks at a portion P, the electrical conductor 18 and the conductive pieces 21 and 21' therein fall down together with the broken plate 13 to interrupt the electrical connection with the conductive pieces 20 and 22 of the adjacent plates 12 and 14. Thus, the circuit of the protective relay 28 is disconnected to urge the contact 29 to its open position. By the opening of the contact 29, the control circuit 30 is opened to stop the escalator driving motor and the footsteps 1 are brought to a halt.

In FIG. 1, reference numerals 31 and 32 designate a guard and a hand-rail movable in association with the footsteps 1, respectively.

From the foregoing description, it will be understood that the safety device of the invention with the above feature is quite effective to protect the escalator mechanism from any heavy damage. The invention is advantageous in the provision of the plurality of comb-shaped plates and the manner of connection of the electrical conductors 17, 18 and 19 with the contact members 26 and 27 by means of the contacts 20, 20', 21, 21', 22 and 22, so that, in the event of breakage of any one of the comb-shaped plates, such broken plate can solely be replaced to restore the arrangement to the normal operative condition.

Although, in the embodiment explained with reference to the drawings, the conductors 17, 18 and 19 are disposed in the body portions of the respective comb-shaped plates 12, 13 and 14, it will be understood that these conductors may be disposed to progressively extend through every tooth portions or the cleats 15 of the combshaped plates.

What is claimed is:

ll. A safety device for an escalator comprising a plurality of comb-shaped plates disposed in juxtaposed relation to each other on a landing plate provided at a landing floor from the escalator, said comb-shaped plates each having a plurality of cleats extending in the direction towards the advancing direction of the escalator and arranged for meshing engagement with cleats of a tread provided on a movable footstep of the escalator, an electrical conductor carried by said comb-shaped plates and disposed transversely across the entire width of said plates, the How of current therethrough being interrupted in the event of breakage of any one of said comb-shaped plates, and means operative in response to the interruption of the current flow through said electrical conductor to stop the operation of the escalator.

2. A safety device according to claim 1, in which said electrical conductor disposed across said comb-shaped plates is divided into a plurality of sections, one for each of said comb-shaped plates, said conductor sections being connected with each other by way of terminal contacts provided on opposite ends thereof.

References (fitted by the Examiner UNITED STATES PATENTS SAMUEL F. COLEMAN, Primary Examiner. 

1. A SAFETY DEVICE FOR AN ESCALATOR COMPRISING A PLURALITY OF COMB-SHAPED PLATES DISPOSED IN JUXTAPOSED RELATION TO EACH OTHER ON A LANDING PLATE PROVIDED AT A LANDING FLOOR FROM THE ESCALATOR, SAID COMB-SHAPED PLATES EACH HAVING A PLURALITY OF CLEATS EXTENDING IN THE DIRECTION TOWARDS THE ADVANCING DIRECTION OF THE ESCALATOR AND ARRANGED FOR MESHING ENGAGEMENT WITH CLEATS OF A TREAD PROVIDED ON A MOVABLE FOOTSTEP OF THE ESCALATOR, AN ELECTRICAL CONDUCTOR CARRIED BY SAID COMB-SHAPED PLATES AND DISPOSED TRANSVERSELY ACROSS THE ENTIRE WIDTH OF SAID PLATES, THE FLOW OF CURRENT THERETHROUGH BEING INTERRUPTED IN THE EVENT OF BREAKAGE OF ANY ONE OF SAID COMB-SHAPED PLATES, AND MEANS OPERATIVE IN RESPONSE TO THE INTERRUPTION OF THE CURRENT FLOW THROUGH SAID ELECTRICAL CONDUCTOR TO STOP THE OPERATION OF THE ESCALATOR. 